1. Technical Field
The present invention relates to a driving circuit for a liquid crystal display device which realizes low power consumption, a liquid crystal display device, a method of driving a liquid crystal display device, and an electronic apparatus.
2. Related Art
In recent years, liquid crystal display devices are widely used for electronic apparatuses, such as various information processing apparatus or flat screen televisions, as display device to replace cathode ray tubes (CRTs). The liquid crystal display devices are classified into various types according to driving methods or the like. For example, an active-matrix-type liquid crystal display device in which pixels are driven by switching elements has the following configuration. Specifically, the active-matrix-type liquid crystal display device has an element substrate on which pixel electrodes arranged in a matrix shape or switching elements correspondingly connected to the pixel electrodes are provided, a counter substrate on which a counter electrode is formed to face the pixel electrodes, and liquid crystal interposed between both substrates.
According to this configuration, if an on potential is applied to a scanning line, switching elements connected to the scanning line become conductive. In the conductive state, if a voltage signal corresponding to a gray-scale level (density) is applied to a pixel electrode through a data line, a charge corresponding to the voltage signal is stored in a liquid crystal capacitor in which liquid crystal is interposed between the pixel electrode and the counter electrode. After the charge is stored, even if an off potential is applied to the scanning line to make the switching element nonconductive, the charge stored in liquid crystal is held by capacitance of the liquid crystal capacitor itself or a storage capacitor provided in parallel with the liquid crystal capacitor. In such a manner, by driving each switching element and controlling the amount of charge to be stored according to the gray-scale level, the alignment state of liquid crystal changes. Therefore, the density changes for each pixel, thereby making it possible to perform gray-scale display.
In the liquid crystal display device, in view of characteristics, features, and uses of an electronic apparatus to which the liquid crystal display device is applied, low power consumption is strongly demanded. On the other hand, in a liquid crystal display device, data lines are driven at a high frequency, and a high swing voltage of 10 volts or more is required for driving a liquid crystal capacitor. Accordingly, a high swing voltage is generally applied to the data lines.
There is suggested a liquid crystal display device which reduces a swing voltage of a voltage signal applied to data lines, thereby realizing low power consumption (for example, see JP-A-2002-196358).
However, according to the configuration disclosed in JP-A-2002-196358, the swing voltage is reduced, but there is no change in frequency at which the data lines are driven. Accordingly, a reduction in power consumption is further demanded.